Problem: Evaluate the following expression when $y = 5$ and $x = 6$. $4$ $y$ $ + 4$ $x$ $ + 9$
Answer: Substitute $5$ for ${y}$ and $6$ for ${x}$ $ = 4{(5)} + 4{(6)} + 9 $ $ = 20 + 24 + 9 $ $ = 53$